diff options
Diffstat (limited to 'bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP192K1FieldElement.java')
| -rw-r--r-- | bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP192K1FieldElement.java | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP192K1FieldElement.java b/bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP192K1FieldElement.java new file mode 100644 index 0000000..0032f35 --- /dev/null +++ b/bcprov/src/main/java/org/bouncycastle/math/ec/custom/sec/SecP192K1FieldElement.java @@ -0,0 +1,213 @@ +package org.bouncycastle.math.ec.custom.sec; + +import java.math.BigInteger; + +import org.bouncycastle.math.ec.ECFieldElement; +import org.bouncycastle.math.raw.Mod; +import org.bouncycastle.math.raw.Nat192; +import org.bouncycastle.util.Arrays; + +public class SecP192K1FieldElement extends ECFieldElement +{ + public static final BigInteger Q = SecP192K1Curve.q; + + protected int[] x; + + public SecP192K1FieldElement(BigInteger x) + { + if (x == null || x.signum() < 0 || x.compareTo(Q) >= 0) + { + throw new IllegalArgumentException("x value invalid for SecP192K1FieldElement"); + } + + this.x = SecP192K1Field.fromBigInteger(x); + } + + public SecP192K1FieldElement() + { + this.x = Nat192.create(); + } + + protected SecP192K1FieldElement(int[] x) + { + this.x = x; + } + + public boolean isZero() + { + return Nat192.isZero(x); + } + + public boolean isOne() + { + return Nat192.isOne(x); + } + + public boolean testBitZero() + { + return Nat192.getBit(x, 0) == 1; + } + + public BigInteger toBigInteger() + { + return Nat192.toBigInteger(x); + } + + public String getFieldName() + { + return "SecP192K1Field"; + } + + public int getFieldSize() + { + return Q.bitLength(); + } + + public ECFieldElement add(ECFieldElement b) + { + int[] z = Nat192.create(); + SecP192K1Field.add(x, ((SecP192K1FieldElement)b).x, z); + return new SecP192K1FieldElement(z); + } + + public ECFieldElement addOne() + { + int[] z = Nat192.create(); + SecP192K1Field.addOne(x, z); + return new SecP192K1FieldElement(z); + } + + public ECFieldElement subtract(ECFieldElement b) + { + int[] z = Nat192.create(); + SecP192K1Field.subtract(x, ((SecP192K1FieldElement)b).x, z); + return new SecP192K1FieldElement(z); + } + + public ECFieldElement multiply(ECFieldElement b) + { + int[] z = Nat192.create(); + SecP192K1Field.multiply(x, ((SecP192K1FieldElement)b).x, z); + return new SecP192K1FieldElement(z); + } + + public ECFieldElement divide(ECFieldElement b) + { +// return multiply(b.invert()); + int[] z = Nat192.create(); + Mod.invert(SecP192K1Field.P, ((SecP192K1FieldElement)b).x, z); + SecP192K1Field.multiply(z, x, z); + return new SecP192K1FieldElement(z); + } + + public ECFieldElement negate() + { + int[] z = Nat192.create(); + SecP192K1Field.negate(x, z); + return new SecP192K1FieldElement(z); + } + + public ECFieldElement square() + { + int[] z = Nat192.create(); + SecP192K1Field.square(x, z); + return new SecP192K1FieldElement(z); + } + + public ECFieldElement invert() + { +// return new SecP192K1FieldElement(toBigInteger().modInverse(Q)); + int[] z = Nat192.create(); + Mod.invert(SecP192K1Field.P, x, z); + return new SecP192K1FieldElement(z); + } + + /** + * return a sqrt root - the routine verifies that the calculation returns the right value - if + * none exists it returns null. + */ + public ECFieldElement sqrt() + { + /* + * Raise this element to the exponent 2^190 - 2^30 - 2^10 - 2^6 - 2^5 - 2^4 - 2^1 + * + * Breaking up the exponent's binary representation into "repunits", we get: + * { 159 1s } { 1 0s } { 19 1s } { 1 0s } { 3 1s } { 3 0s} { 3 1s } { 1 0s } + * + * Therefore we need an addition chain containing 3, 19, 159 (the lengths of the repunits) + * We use: 1, 2, [3], 6, 8, 16, [19], 35, 70, 140, [159] + */ + + int[] x1 = this.x; + if (Nat192.isZero(x1) || Nat192.isOne(x1)) + { + return this; + } + + int[] x2 = Nat192.create(); + SecP192K1Field.square(x1, x2); + SecP192K1Field.multiply(x2, x1, x2); + int[] x3 = Nat192.create(); + SecP192K1Field.square(x2, x3); + SecP192K1Field.multiply(x3, x1, x3); + int[] x6 = Nat192.create(); + SecP192K1Field.squareN(x3, 3, x6); + SecP192K1Field.multiply(x6, x3, x6); + int[] x8 = x6; + SecP192K1Field.squareN(x6, 2, x8); + SecP192K1Field.multiply(x8, x2, x8); + int[] x16 = x2; + SecP192K1Field.squareN(x8, 8, x16); + SecP192K1Field.multiply(x16, x8, x16); + int[] x19 = x8; + SecP192K1Field.squareN(x16, 3, x19); + SecP192K1Field.multiply(x19, x3, x19); + int[] x35 = Nat192.create(); + SecP192K1Field.squareN(x19, 16, x35); + SecP192K1Field.multiply(x35, x16, x35); + int[] x70 = x16; + SecP192K1Field.squareN(x35, 35, x70); + SecP192K1Field.multiply(x70, x35, x70); + int[] x140 = x35; + SecP192K1Field.squareN(x70, 70, x140); + SecP192K1Field.multiply(x140, x70, x140); + int[] x159 = x70; + SecP192K1Field.squareN(x140, 19, x159); + SecP192K1Field.multiply(x159, x19, x159); + + int[] t1 = x159; + SecP192K1Field.squareN(t1, 20, t1); + SecP192K1Field.multiply(t1, x19, t1); + SecP192K1Field.squareN(t1, 4, t1); + SecP192K1Field.multiply(t1, x3, t1); + SecP192K1Field.squareN(t1, 6, t1); + SecP192K1Field.multiply(t1, x3, t1); + SecP192K1Field.square(t1, t1); + + int[] t2 = x3; + SecP192K1Field.square(t1, t2); + + return Nat192.eq(x1, t2) ? new SecP192K1FieldElement(t1) : null; + } + + public boolean equals(Object other) + { + if (other == this) + { + return true; + } + + if (!(other instanceof SecP192K1FieldElement)) + { + return false; + } + + SecP192K1FieldElement o = (SecP192K1FieldElement)other; + return Nat192.eq(x, o.x); + } + + public int hashCode() + { + return Q.hashCode() ^ Arrays.hashCode(x, 0, 6); + } +} |